Receiving system



2 Sheets-Sheet l H. H, BEVERAGE RECEIVING SYSTEM Original Filed Nov. 8, 1929 jam. 2%, 1936.

AAAAAA vvvvv INVENTOR HAROLD H. BEVERAGE BY H ATTORNEY 50 rier was reduced to some intermediate frequency, thereto which Patented Jan. 28, 193 2,028,860

UNITED STATES PATENT OFFICE $028,860 RECEIVING SYSTEM Harold H. Beverage, Riverhead, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application November 8, 1929, Serial No. 405,615 Renewed May 24, 1933 3 Claims. (Cl. 250-8) This invention relates to the art of radio sigquency energy of such ultra high frequencies at nalling and has for one of its objects the provithe receiving end. sion of a novel method and means for receiving For a maximum rate of keying speed, it has and rectifying directly extremely high or ultra already been indicated that a minimum of 10 10 consideration. For the speed of 100 words per filled in due to transients. The rounded end ef- 10 second. because, when it was attempted with prior receiv- At the receiver for uniform legible signals it me ircuits t amp fy th igh frequency curis highly desirable to keep the shape of dots as rents directly, parasitic oscillations and undue of dots it has been found desirable and necessary reception impossible. to have a minimum of 10 cycles of carrier fre- T0 ob a the foregoing difiielllties and t proquency per dot of keyingfrequency. For the speed vide a novel method and means whereby extreme- 2O audio range it is entirely satisfactory for code reampl fi especially designed to p y eXtreme- 25 received carrier. However, with the advent of Over the ends of thecharacters. highly improved automatic receivers which trace n the accompanying aw In Which I have 30 signal characters upon a, tape, ch as di l d illustrated several embodiments of my invention at a speed of the order of magnitude of thousands high frequency p fi av a p a ty of 35 of words per minute. At the transmitter, thereamplification Stages, fore, the keying speed would have to be corre- Figure 2 ShOWS a Simple form o e iv spondingly increased. Turning to facsimile and System in which the p p es f my nvention printer work even higher keying speeds are reare app quired. For television, a transmitter should be Figure 3 Shows how my invention may be ap- 40 keyed at 100,000 cycles for a square modulation plied to a receiver having diversity in q y, envelope at the receiver; and, with reference to and the most recent types of facsimile and television s 4 mecaies Tecelvmg Sy$ten 1 p transmitters, carriers having a frequency of the t SubJect matter of my mventlon havlng order of magnitude of 20,000,000 cycles per secm q 45 end are radiated Turning to Figure 1, in which I have sh w Heretofore when dealing at the receiver with SFhematlcany hlgh frequefncy amphfier espesuch ultra high frequencies, the transmitted carsay, to 100,000 cycles by heterodyning, and the may be coupled to an rgy colheterodyned beat energy was then detected and extremely high used for translation purposes. The reason for h v th a frequency as th input such heterodyning was due, of course, to the from the amplifier at point B by any suitable fact that it was impossible to amplify high frecoupling device such as the electrostatically 55 provides a path shielded transformer shown. Although two stages have been indicated, any desired number may be used.

Input energy at A is fed through a transformer electrostatically shielded by means of shield E. to the input circuit 8 of the first screen grid amplifier tube 10. To. prevent radio frequency. currents from travelling directly to another stage or to other points through the control electrode lead l2, theinductance coil of tuned circuit 8 is grounded through a blocking condenser l4, which of low impedance forthe high frequency currents to ground. To further insure the passage to ground of radio frequency currents in the lead l2, a radio frequency choke coil I6 is placed therein and, the potential supply end thereof is short circuited toground for radio frequency currents by means of a condenser l8.

To prevent feed back from the anode toythe control electrode of electron discharge device 10, that device ispreferably having a screen grid 2% which effectively prevents interelectrode feed back. Asan added precaution the s 7 id grid is grounded for radio irequency currentsthrough a blockingcondenser 22 as is-also the normally ungrounded side of the cathode 2d, through a condenser 26.

The output circuit 28 of tube Ill is grounded similarly for the-purpose of confining the flow of radio frequency currents along certain elements,

more particularly,-each element 21, 29 of tunable circuit 28'isseparately grounded for radio frequency currents.

Energy from the output circuit is fed'through a blocking condenser 30 to the input side of tube 32 similar in type to tube II). To provide a definite bias for the control grid oftube 32 a resistance as is connectedjin the grid circuit of tube 32,-

and is grounded for radio frequency currents through a blocking condenser 36 to further preventthe passage of radio frequency currents along the bias lead l2. The output circuit of tube 32 contains apparatus similar to that already densers to, or in the anode supply lead are pro-' compartment;

described andhence need not be explained'in detail.

Chokes 38and M) in the cathode energy supply lead 42 for the tubes are provided toprevent the flow of radio frequency currents therein and thereby prevent setting up of interactions and oscillations. To further prevent the passage of radio frequency currents into the cathode energizing source capacities 44 are provided which combined have a relatively low impedance for radio frequency currents thereby efiectively shunting any such currents whichmay be; pres-- ent. to ground. An additional condenser 46 V v I V the energy terminal of the cathode supply lead. A choke and a condenser 48 are connected to the screen grid potential lead 52, andchokes 54, '58 and convided for a similar purpose. V From the precautions described tobe taken in the construction of the radio frequency amplifier, it should be apparent as to means to be used-in connection with the'rectifier to prevent distortion therein. In addition, metallic shields should be placed about the apparatus included in each stage and about each tube, and the power supply filters should be in a separate shielded In Figure 2 I have shown" htw'mt improved amplifier' described in detail in connection with Figure i may be applied to a simple receiver system. 'Ener'gy collected upon antenna .64 is-fed supplied by a battery i0, and

of the screen grid type scribed,'it should be understood tube for photographic re- {by means of the a 7 output or" a generator G which gen 2,02asco amplifier E6 having a circuit of the type shown in Figure 1. The amplified extremely high frequency currents at directly into a bias matically at 58 to control a thermionic relay R.

A typical thermionic relay for controlling an electrostatic high speed ink recorder is indicated. The anode voltage for bias rectifier tube 68 is the anode current fiows through resistance 12. The voltage drop across. resistanceEZ controls tube 14, and also tube 82. The voltage drop across resistance 18 in the anode circuit or tube i l controls another tube '80 which is paired with tube 82.

When there is no signal voltage arriving, 68is biased to cut off the anode current, so there" is no voltage drop across resistance 12, thus allowing tubes 14 and 82 to pass an anode current through resistances l8 and te'respectively/The voltaged rop acrossresistance 18 biases-tube 89 to cutofi. Hence, with no'signal no anode current 8% and electrostatic control coming in,- tube 7 passes through resistance plate 9!] is at high positive potential. v I

At the same time, tube-82 ispassing anode cure rent through resistance 86-, causing electrostatic control plate 88 to be at a' lower potential than it is amplified by amplifier E8 and is fed through transformer B-to the grid of the bias rectifier tube 68, causing an anode current to-fiow in resistance 12. Tubes 14 and 82 the anode currents, and asthere is now no voltage drop across resistance 18, tube 80 is biased to pass an anode-current which produces a drop in voltage across resi'stance 86., Plate'fifl ndw becomes less positive than plate 88, an'd the ink jet is deflected towards plate 88'.

While a typical thermionic relay has been dethat other devices, such as gaseous cording, or a circuit controlling the current 111 the moving coil of a high speed recorder could have been used. The thermionic relay could also have been used to key an oscillator or lower frequency suitable for transfer over a wire line the distant point, or it could hayebeen used to control a mechanical relay. this invention should be used with thermionic,

. gaseous, or mechanical relays, selecting in each the output circuit B are fed rectifier shown diagram nal voltage arriving at 84,

are then biased to cutoff It is intended that tube In orderto r'educe fading effects, it is desirable to transmit the same signal modulation on two or more frequencies. My invention as applied to such a'system is described in Figure 3,:where at Fl, I utilize a radio frequency amplifien 66 tuned to a'irequency FL, and at F2, I utilizea second amplifier 6E tuned to a irequency'FZ Although both amplifiers FI and F2 are connected to a single- 'collector 64 at A, lt is obvious that they may be separately connected {or coupled to geographically spaced collectors or antennae.

' The amplified output'ot the two amplifiers Ff and'Fl of extremelyhighirequencies are ap= 7 plied to rectifier .55 and .55'Wand rectified outputs of. the rectifiers are combined relay R, which in turn keys t e rectified, The

crates a he quency, and a spacing wave of another frequency. Since these two frequencies have been found to fade differently, it would be possible to reduce the fading effect by making use of both the marking and spacing wave. To accomplish this with the arrangement of Figure 3, amplifier FI wave. In this case, the rectifiers 55 and 55 would have their output circuits connected differentially to the. relay R so that the effects of the space and mark waves would be cumulative on the relay R.

In Figure 4, I have shown my invention as applied to a diversity receiving system having geographically spaced collectors 64 for the purpose of reducing fading effects. Energy collected upon each of the antennae is amplified in radio frequency amplifiers 66 and 66 tuned to a frequency F i and F2 which is then fed at B to full wave rectifiers 09 and 99'. The outputs of the two rectifiers are combined in a common resistance I68 which is connected through a bias bated end of the resistance #68 is connected through a bias battery I10 to the grid I1I of tube I12, which tube has its energy and high potential plate supplied by a battery series with a relay R, the plate circuit being com- I1I of tube I12 is normally so biased by battery H that plate current will flow under conditions when no signal is received. In this case plate current flows through plate I12, filament '55, the battery I13, and relay R. However, when signals are received through antennas 64 and 64', then after passing through the amplifiers FI and F2, and rectifiers 99 and 99' to the common point I16 due to the voltage drop occurring across resistance I68, the common point I16 becomes negative with respect to its previous potential, and therefore, the normal bias on grid I1I of tube I12 is overcome. It should be understood. however, that the cut off potential of tube I 12 depends upon both the voltage and potential of the bias battery I and the characteristics of the tube I12. The anode current of the tube I12 is shown controlling a nonthermionic relay R, which in turn controls translator T.

It is to be understood that in Fig. 4 may include radio frequency amplifiers FI and F2 tuned to diiferent frequencies.

Although a non-thermionic relay is shown, a preferred arrangement, would be to use the scheme of Figure 4 in connection with the therwould be that tube I12 would normally be ad- Justed to pass an anode current with no signal arriving, as mentioned in detail above, but as soon ii? negative, cutting off the anode current, which the system shown is just the reverse of the operation of tube 68 of Figure 2.

value necessary anode current of tube I12 to zero, the thermionic relay will operate between two fixed limits, corresponding to the conditions of normal and zero anode current in tube I12, respectively.

It is obvious that more than two geographically separated antennae could be used by connecting the output of the multiplicity of rectifiers td the common resistance I68.

Having thus described my invention, what I claim is:

l. A receiving system for extremely high frequency signals of the order of 20,000,000 cycles per second transmitted at a plurality of frequencies comprising a plurality of geographically spaced antennas, a radio frequency amplifier coupled to each of the antennas and each tuned to a different one of the transmitted frequencies, each of said amplifiers comprising a plurality of screen grid electron disto reduce the the output of fiers, circuit means including a relay t cdmbine the rectified energies, and translating means responsive to the combined energy.

2. A receiving system for substantially eliminating the fading effects of signal energy in the order of 20,000,000 cycles and modulated at a frequency of substantially 2,000,000 cycles, comof geographically spaced anof 10 cycles of carrier frequency per dot of modulated frequency, comprising a plurality of geographically spaced antennas, a radio frequency amplifier for each of the said antennas, a full to give a substantially square dot formation of the modulated frequency, and means for combining the modulated frequency of each full wave rectifier comprising a resistance HAROLD H. BEVERAGE. 

